NAME
Math::Random::ISAAC - Perl interface to the ISAAC PRNG Algorithm
$Id: README 5756 2009-03-25 19:13:54Z FREQUENCY@cpan.org $
DESCRIPTION
As with other Pseudo-Random Number Generator (PRNG) algorithms like the
Mersenne Twister (see Math::Random::MT), this algorithm is designed to
take some seed information and produce seemingly random results as
output.
However, ISAAC (Indirection, Shift, Accumulate, Add, and Count) has
different goals than these commonly used algorithms. In particular, it's
really fast - on average, it requires only 18.75 machine cycles to
generate a 32-bit value. This makes it suitable for applications where a
significant amount of random data needs to be produced quickly, such
solving using the Monte Carlo method or for games.
The results are uniformly distributed, unbiased, and unpredictable
unless you know the seed. The algorithm was published by Bob Jenkins in
the late 90s and despite the best efforts of many security researchers,
no feasible attacks have been found to date.
SYNOPSIS
use Math::Random::ISAAC;
my $rng = Math::Random::ISAAC->new(@seeds);
for (0..30) {
print 'Result: ' . $rng->irand() . "\n";
}
PURPOSE
The intent of this module is to provide single simple interface to the
two compatible implementations of this module, namely,
Math::Random::ISAAC::XS and Math::Random::ISAAC::PP.
If, for some reason, you need to determine what version of the module is
actually being included by "Math::Random::ISAAC", then:
print 'Backend type: ', $Math::Random::ISAAC::DRIVER, "\n";
In order to force use of one or the other, simply load the appropriate
module:
use Math::Random::ISAAC::XS;
my $rng = Math::Random::ISAAC::XS->new();
# or
use Math::Random::ISAAC::PP;
my $rng = Math::Random::ISAAC::PP->new();
COMPATIBILITY
This module was tested under Perl 5.10.0, using Debian Linux. However,
because it's Pure Perl and doesn't do anything too obscure, it should be
compatible with any version of Perl that supports its prerequisite
modules.
If you encounter any problems on a different version or architecture,
please contact the maintainer.
AUTHOR
Jonathan Yu
ACKNOWLEDGEMENTS
* Special thanks to Bob Jenkins for
devising this very clever algorithm and releasing it into the public
domain.
* Thanks to John L. Allen (contact unknown) for providing a Perl port
of the original ISAAC code, upon which "Math::Random::ISAAC::PP" is
heavily based. His version is available on Bob's web site, in the
SEE ALSO section.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Math::Random::ISAAC
You can also look for information at:
* AnnoCPAN: Annotated CPAN documentation
* CPAN Ratings
* Search CPAN
* CPAN Request Tracker
* CPAN Testing Service (Kwalitee Tests)
* CPAN Testers Platform Compatibility Matrix
REPOSITORY
You can access the most recent development version of this module at:
L
If you are a CPAN developer and would like to make modifications to the
code base, please contact Adam Kennedy , the repository
administrator. I only ask that you contact me first to discuss the
changes you wish to make to the distribution.
FEEDBACK
Please send relevant comments, rotten tomatoes and suggestions directly
to the maintainer noted above.
If you have a bug report or feature request, please file them on the
CPAN Request Tracker at . If you are able to submit
your bug report in the form of failing unit tests, you are strongly
encouraged to do so. Regular bug reports are always accepted and
appreciated via the CPAN bug tracker.
SEE ALSO
Math::Random::ISAAC::XS, the C/XS optimized version of this module,
which will be used automatically if available.
, Bob Jenkins' page
about ISAAC, which explains the algorithm as well as potential attacks.
CAVEATS
KNOWN BUGS
There are no known bugs as of this release.
LIMITATIONS
* There is no method that allows re-seeding of algorithms. This is not
really necessary because one can simply call "new" again with the
new seed data periodically.
* There was no method supplied to provide the initial seed data. On
his web site, Bob Jenkins writes:
Seeding a random number generator is essentially the same problem as
encrypting the seed with a block cipher.
But he also provides a simple workaround:
As ISAAC is intended to be a secure cipher, if you want to reseed
it, one way is to use some other cipher to seed some initial version
of ISAAC, then use ISAAC's output as a seed for other instances of
ISAAC whenever they need to be reseeded.
* There is no way to clone a PRNG instance. I'm not sure why this is
might even be necessary or useful. File a bug report with an
explanation why and I'll consider adding it to the next release.
LICENSE
Copyleft 2009 by Jonathan Yu . All rights reversed.
I, the copyright holder of this package, hereby release the entire
contents therein into the public domain. This applies worldwide, to the
extent that it is permissible by law.
In case this is not legally possible, I grant any entity the right to
use this work for any purpose, without any conditions, unless such
conditions are required by law.
The full details of this can be found in the LICENSE file included in
this package.
DISCLAIMER OF WARRANTY
The software is provided "AS IS", without warranty of any kind, express
or implied, including but not limited to the warranties of
merchantability, fitness for a particular purpose and noninfringement.
In no event shall the authors or copyright holders be liable for any
claim, damages or other liability, whether in an action of contract,
tort or otherwise, arising from, out of or in connection with the
software or the use or other dealings in the software.